The present invention relates to a polyarylene sulfide resin composition. In particular, the invention relates to a polyarylene sulfide resin composition which has improved surface properties, fluidity and specific gravity and is inexpensive and a molded article prepared by molding the same.
Recently, thermoplastic resins which have high resistance to heat and chemicals and are flame-retardant have been demanded as materials used for components in electrical and electronic appliances, automobile devices and chemical instruments. A polyarylene sulfide resin represented by polyphenylene sulfide is one of the resins satisfying this demand. Polyarylene sulfide has a good cost performance, so that the demand therefor has increased. Generally, the polyarylene sulfide resin is blended with a large amount of a filler with the purpose of reducing the cost and warpage thereof.
However, the composition thus obtained has disadvantages due to the influence of the filler used. The filled composition provides for molded articles poor in surface smoothness and such composition exhibits lowered fluidity and increased specific gravity. Though it has been expected to apply filled polyarylene sulfide compositions to a field requiring excellent heat resistance and surface properties, for example, automobile lamp reflector, such application has not been realized as yet.
Generally, the following methods are employed in order to improve the disadvantages of filled polyarylene sulfide compositions:
(1) the use of a low-molecular weight polymer excellent in fluidity, and PA1 (2) the reduction in the amount of the filler added. PA1 (A) 100 parts by weight of a polyarylene sulfide resin and PA1 (B) 5 to 400 parts by weight of a hollow microspherical filler which comprises 20 to 80% by weight of SiO.sub.2 and 20 to 80% by weight of Al.sub.2 O as major components and has a specific gravity of 1.0 to 2.5 and an average particle diameter of 1 to 100 .mu.m, and a molded article for light reflection such as a lamp reflector which is prepared by molding the same.
However, these methods cannot sufficiently solve the disadvantages.
For example, method (1) has disadvantages in that the resulting composition exhibit lowered mechanical strength, the method has no effect upon reducing the specific gravity and it cannot sufficiently improve the surface properties, while method (2) has disadvantages in that it yields a molded article lowered in heat resistance (such as thermal deformation temperature) and resistance to warpage and deformation and it brings about an unavoidable increase in the cost, though it is effective in lowering the specific gravity.